1. Field of the Invention
The present invention relates to a washing method and apparatus of a screw for extruder and the like.
2. Prior Art
One example of a screw washing machine is described in the Japanese Utility Model Publication No. S63-16495. In this washing machine, a plurality of support roller assemblies, each comprising a pair of rollers, are disposed in a casing so as to support thereon a screw rotatably and horizontally. The support roller assemblies are rotated by power, and the screw is rotated by friction force. A rail is provided parallel to the axial direction of the screw, and on the rail is a traveling stand which is moved by a reciprocation means. A water jet assembly, having a nozzle tip that faces the screw, is mounted on the traveling stand. Two nozzle holes are provided on the nozzle tip, one is perpendicular and the other is inclined 15-45 degrees against the axial direction of the screw.
The above-described washing machine has some problems. Many unwashed areas remain on the screw after one washing process since the nozzle hole of the washing machine is positionally fixed and the water cannot reach every part of the screw according to the angle of the screw thread surface against the screw axial direction.
Therefore, a repetitious washing process must be taken so as to clean the entire screw surface. In addition, since the washing machine has two holes in the nozzle, a great amount of water is needed. The pump capacity becomes larger as well as the a motor used for driving the pump. As a result, the electric power consumption becomes very large.